Luminaires of the type which typically include a prismatic reflector for the purpose of efficiently directing the light output in a desired pattern, utilize a high intensity light source which can generate a significant amount of heat and radiation. Without design consideration, the heat and radiation could damage the reflector. An example of a luminaire which utilizes a prismatic reflector constructed of an acrylic material, can be found in U.S. Pat. No. 4,903,180 issued to Taylor et al on Feb. 20, 1990 and assigned to the same assignee as the present invention, such patent being hereby incorporated by reference. Because the prismatic reflector in such a luminaire is constructed of an acrylic material, in order to prevent damage to the reflector, it is necessary to use a low wattage light source which does not produce heat and radiation at a damaging level to the prismatic reflector of a given size. Alternatively, if a higher wattage light source is preferred, one could be required to provide a prismatic reflector which is significantly increased in size to accommodate the higher heat and radiation levels associated with the higher wattage lamps. Exemplary values for the reflector size and lamp wattage size for a luminaire such as described in U.S. Pat. 4,903,180 are: a 25 inch bottom diameter, 12 inch top diameter and 14 inch height for the reflector and, for the light source, a 400 watt high intensity discharge lamp is used. With such a configuration, it has been measured that the reflector is exposed to a 55.degree. C. temperature which is well within the limit of 85.degree. C. for acrylic materials.
For an industrial or commercial lighting application, it would be advantageous to provide a luminaire that could deliver a higher light output than that which can be achieved using a 400 watt lamp. For instance, some lighting applications require the use of a 1000 watt high intensity light source. If such a light source were to be utilized, it is estimated that the dimensions of the reflector would have to be on the order of 50% larger than that used for the 400 watt lamp. Such an increase in reflector size is impractical given the fact that an acrylic reflector will be formed using an injection molding manufacturing process. Such a process is inherently expensive since the tooling cost of making and operating the larger sized mold would be extensive. Moreover, one cannot merely increase the size of a reflector by 50% without first considering design changes to insure the integrity of the actual reflector structure and maintain the desired light distribution properties; it is probable that the increased size would result in a weaker structured product susceptible to damage having poorer optical properties. Accordingly, it would be advantageous to provide a luminaire with a prismatic reflector that could accommodate a range of lamp wattages and yet maintain the same size and structure for the reflector which would be capable of withstanding the range of heat and radiation levels output by the various sized lamps.